Portland cement



a. QUIVHUSI l IUNS,

COATING OR PLASTIC.

Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE ANDREW LUNDTEIGEN, OF KANSAS CITY, MISSOURI, AND GUY O. GARDNER, OF CHA- NUTE, KANSAS, ASSIGNORS TO ASH GROVE LIME & PORTLAND CEMENT COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION OF MAINE PORTLAND CEMENT No Drawing.

This invention relates to improvements in Portland cement, and refers more particularly to a quick hardening cement which besides giving the usual working time, or initial set of the normal commercial Portland cement, has in addition the advantage of quick hardening and increased strength.

As is well known, Portland cement is a product obtained by finely pulverizing clinker produced by calcining to incipient fusion an intimate and properly proportioned mixture of argillaceous and calcareous materials withno addition subsequent to calcination, except (water and calcined or uncalcined) gypsum.

The product which forms the subject matter of the present invention is properly a Portland cement which is the result of carefully controlled operations compared to the present usual methods of manufacturing cement. Furthermore, the improved product has added thereto materials which produce the quick hardening effect as will hereinafter be described in more detail.

A typical operation for making the product of the present invention is as follows: To begin with the argillaceous material, or clay 1s selected from three sourcesone conslsting of a relatively high aluminum clay, another of a0 clay of relatively high silica content, and a clay containing a. small percentage of ron.

The argillaceous materials and the limestone (calcium carbonate), are first crushed to pass a screen of one and one-half inch mesh,

or under. The clay and limestone are then i combined in proper proportions and ground with water in a ball mill to twenty mesh or under. (The fines of this mixture proceed to a tube mill and the coarse material is returned to be re ound.) In the tube mill the fines are furt er pulverized, in the presence of water, samples being taken off at intervals of not more than an hour and tested for fineness and analyzed to assure proper proportlonmg of the calcium carbonate, alumina and silica. The mix is so adjusted that the calcium carbonate content of the rawmixis substantially fitrmmigher than the normal oFfisfial'ifiiiiEf This proportion Wlll vary according to composition of the raw mate- Application filed July 11,

rials and the character of the final product desired.

The mixture is then conducted to a slurry tank, which is equipped with air and mechanical agitators, and from the slurry tank the mix is transferred to correcting basins or kiln feed basins. Again the mix is tested and analyzed, and any deficiency in lime, alumina or silica is corrected. From the feed basins the slurry is elevated or pumped into a feed trough over the intake of the kiln, which is fired to a temperature in the neighborhood of 27 00 F. Any suitable fuel may be used for firing. Oil or gas perhaps are most satisfactory as they do not-contaminate the clinker by conveyors to QIlllSlliIl and rindin means, where it is l l tjerized so that 501115 thing over twent er hundred mes 1 screen.

p to t is point in the process the separate stages or features of the operation have been substantially the normal practice in cement making with the exception perhaps of I the quenching of the clinker on its discharge from the kilns. Here, however, we have a 85 radical change in the methods heretofore used, in that there is added a pre-mixed combination of inorganic chlorides to an amount not to exceed 52 according to the nature of the ch on e or chlorides used. A typical 90 instance may consist of 0.9% sodium chloride and 0.1%; calcium ch on e. ese or other chlori es a one or in com ination so more or less of aluminum stearate or any other metal soa WElCH serves largely as a uenched lubricant in th e fiualglfilltliflgg eration. In

place of metal soap directly a (led Elie" invention contemplates the use of alternative mzgterials, such as mineral animalnra e- 5 ta le oils or 0617M mother fag; acids, or any type of ma erla w wou unction as a grindin '0 last 'zi a t water re- P l and P. aws tfie rammar-9.1.3. the lifiril"'gfiiiiifiat addition of aluminum stearate, differentiates the prodnot materially from the common well-known Portland cement of commerce. It is believed 15 that the chlorides function as hydration accelerators, or produces what may be termed as a catalytic acceleration of the hydration action during the hardening of the cement or concrete when laid.

The oil or metal soaps by reason of their water repellent action tend to prevent sack hardening. Before 'final grinding there may be addedalso uick lime to an amount of five-tenths of one per cent niglfegl'less, which serves to absorbtli''water or moisture introduced by the chemicals or still present in the quenched clinkers, and at the same time reacts on free and loosely held carbon dioxide (CO Also the lime increases the plastic-- ity of the final product, and prevents sack hardening in storage by reason of its avidity for moisture being greater than that of the cement.

The final grinding results in a product which is preferably pulverized to at least ninety-five per cent passing a two hundred mesh screen as compared to the standard Portland cement in which normally seventyeight per cent is required to pass a two hun- 40 dred mesh screen.

This improved Portland cement product then is truly of the nature of Portland cement, and gives, or permits the normal working period, and in addition affords the attributes of a quick hardening cement. There is no excess of heat produced during the setting which would cause deterioration, but on the other hand the hardening of the cement is by a progressive rate. There is a certain amount of heat produced, but it is not in an amount sufficient to dry the mix to the extent that it efiects hydration adversely.

It is found, however, that there is sufiicient heat produced to be beneficial to the proper hardening in cold weather. The cement, which is the product of this process, has an increased tensile strength, and crushing strength, as compared with the common Portland cement. Furthermore it has the ability of hardening within a period of one day, to produce strength which is comparable to that ordinarily attained by present standard specification Portland cement at a period of twenty-eight days. The periods of workabili 1 .J-n 1 ity and setting are substantially "the same as the common type of Portland cement.

A typical illustration of strengths of hardened mortars and coucretes made by this process is as follows:

For comparison the strength of these mortars at one day are greater than present standard specification for Portland cement requires at twenty-eight days, and the twentyeight day strength of this quick-hardening cement is more than 50% greater than standard specification for Portland cement requires at same period and of same mix.

The addition of chlorides in the manufac ture of the improved product thereinbefore described is effected by adding nh@(le1s of odium and calcium. The invention, ow-

-ever, contemplates that other chlorides may as well be used, such as MW barium ma nesium otasslum or 0 ers per- M y i'i'ierciq 'conditlsns.

I claim as my invention:

1. A method of making a quick hardening cement which comprises adding to a clinker formed from argillaceous and calcareous materials, gypsum and a mixture of calcium and sod ilgl} gllffimsnin amount suflicient to act as" accelerators for hardening in the final product, and grinding the aggregate so produced in the presence of a lubricant to the extent that at least 78 per cent passes a 200- mesh screen.

2. A method of making a quick hardening cement which comprises adding to a clinker formed from argillaceous and calcareous materials, gypsum and a mixture of calcium and sodium chlorides in amount sufiicient to act as accelerators for hardening in the final product, and grinding the aggregate so produced in the presence of an insoluble soa to the extent that at least 78 per cent passes a ZQQgnesh screen.

3. A method of making a quick hardening cement which comprises adding to a clinker formed from argillaceous and calcareous ma- QOMPOSITIONS, COATING R PLASTIC.

terials, gypsum and a mixture of calcium and sodium chlorides in amount suflicient to act as accelerators for hardening in the final product, and grinding the aggregate so produced in the presence of a lubricant to the extent that at least 78 per cent passes a 200- mesh screen, and adding before the completion of the grinding a small amount of quick-lime. 1o 4. A quick hardening cement comprising i a fused and ground mixture of limestone and argillaceous material, which mixture contains both sodillrljfl calcium chlorides in i amounts sufficient to act as accelerators of hardening.

5. A quick hardening cement comprising a fused and ground mixture of limestone and argillaceous material, which mixture contains both sodium and calcium chlorides in amounts sufficient to act as accelerators of hardening, said mixture also containing a water re ellent material.

6. K quick hardening cement comprisim a fused and ground mixture of limestone an argillaceous material, said mixture containing both sodium and cal.cillm chlorid s in amounts suflicient to act as accelerators of hardening, the sodium chloride being in substantial excess over the calcium chloride. 36 7 A quicE hardening cement comprising a fused and ground mixture of limestone and argillaceous material, said mixture containing both calcium and sodium chlorides in an amount o f le s s man l p,ercent, the sodium chloride being present in substantial excess over the calcium chloride, the mixture also containing an insoluble soap which acts as a water gpelle nt material and havingii corporate therewlth lime in small amounts. 0 ""ANDRE'WIUNDTEIGEN.

GUY O. GARDNER. 

